3 people can line up for 3 cashiers in 6 ways.
This is a permutation type of question. Formula for permutation is given as
nPr = [tex]\frac{n!}{(n-r)!}[/tex]
where
P = permutation
n = total number of objects = 3
r = total number of objects selected = 3
nPr = [tex]\frac{3!}{(3-3)!}[/tex]
nPr = [tex]\frac{3 * 2 * 1}{1 }[/tex]
nPr = [tex]\frac{6}{1}[/tex]
nPr = 6
therefore the number of ways needed is 6.
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